Aberrant functional connectivity of neural circuits associated with thought-action fusion in patients with obsessive-compulsive disorder

Aberrant function of the salience network related to maltreatment experiences during thought-action fusion

Childhood maltreatment (CM) causes early deviations in cognitive and affective processes, leading to future adaptation failures and psychopathology. Specifically, CM has been linked to cognitive distortions, and recent studies have focused on the impact of CM on the higher level of metacognitive beliefs. However, only a few studies have revealed the neural mechanisms underlying the association between altered metacognition and CM. Therefore, this functional magnetic resonance imaging (fMRI) study investigated the neural correlates of thought-action fusion (TAF) tendency and CM experiences. Overall, 40 young and healthy adults (21 men) participated in this study and underwent fMRI during the TAF task as well as psychological evaluation for CM, TAF tendency, anxiety, and depressive symptoms. During the TAF task, they were asked to read negative (Neg) or neutral (Neu) statements about neutral or close people (CP). Notably, significant activations were found in regions such as the bilateral anterior insula, dorsal anterior cingulate cortex (dACC), caudate, thalamus, medial prefrontal cortex, precuneus, and right amygdala in the NegCp > NeuCP contrast. Furthermore, anterior insula and dACC activities were significantly correlated with total scores of CM experiences and TAF. Exaggerated TAF tendency in persons with CM experiences was associated with increased response of the anterior insula and dACC, which are two core hubs of the salience network. Our results therefore seem to suggest insights for a better understanding of the neural mechanisms underlying metacognitive beliefs related to CM experiences.

Neural mechanisms of acceptance-commitment therapy for obsessive-compulsive disorder: a resting-state and task-based fMRI study

BACKGROUND

There is growing evidence for the use of acceptance-commitment therapy (ACT) for the treatment of obsessive-compulsive disorder (OCD). However, few fully implemented ACT have been conducted on the neural mechanisms underlying its effect on OCD. Thus, this study aimed to elucidate the neural correlates of ACT in patients with OCD using task-based and resting-state functional magnetic resonance imaging (fMRI).

METHODS

Patients with OCD were randomly assigned to the ACT (n = 21) or the wait-list control group (n = 21). An 8-week group-format ACT program was provided to the ACT group. All participants underwent an fMRI scan and psychological measurements before and after 8 weeks.

RESULTS

Patients with OCD showed significantly increased activation in the bilateral insula and superior temporal gyri (STG), induced by the thought-action fusion task after ACT intervention. Further psycho-physiological interaction analyses with these regions as seeds revealed that the left insular-left inferior frontal gyrus (IFG) connectivity was strengthened in the ACT group after treatment. Increased resting-state functional connectivity was also found in the posterior cingulate cortex (PCC), precuneus, and lingual gyrus after ACT intervention Most of these regions showed significant correlations with ACT process measures while only the right insula was correlated with the obsessive-compulsive symptom measure.

CONCLUSIONS

These findings suggest that the therapeutic effect of ACT on OCD may involve the salience and interoception processes (i.e. insula), multisensory integration (i.e. STG), language (i.e. IFG), and self-referential processes (i.e. PCC and precuneus). These areas or their interactions could be important for understanding how ACT works psychologically.

Primary states of consciousness: A review of historical and contemporary developments

Primary states of consciousness are conceived as phylogenetically older states of consciousness as compared to secondary states governed by sociocultural inhibition. The historical development of the concept in psychiatry and neurobiology is reviewed, along with its relationship to theories of consciousness. We suggest that primary states of consciousness are characterized by a temporary breakdown of self-control accompanied by a merging of action, communication, and emotion (ACE fusion), ordinarily segregated in human adults. We examine the neurobiologic basis of this model, including its relation to the phenomenon of neural dedifferentiation, the loss of modularity during altered states of consciousness, and increased corticostriatal connectivity. By shedding light on the importance of primary states of consciousness, this article provides a novel perspective on the role of consciousness as a mechanism of differentiation and control. We discuss potential differentiators underlying a gradient from primary to secondary state of consciousness, suggesting changes in thalamocortical interactions and arousal function. We also propose a set of testable, neurobiologically plausible working hypotheses to account for their distinct phenomenological and neural signatures.

Heightened but Inefficient Thought-Action Fusion in Obsessive-Compulsive Disorder: New Insight From a Multiple Trial Version of the Classic Thought-Action Fusion Experiment

OBJECTIVE

Thought-action fusion (TAF), which is a tendency to make the relationship between one's thoughts and external consequences, is a dysfunctional belief linked to obsessive-compulsive disorder (OCD). While the TAF is commonly evaluated using the Thought-Action Fusion Scale (TAFS), it cannot fully reflect the actual experience of experimentally evoked TAF. In the present study, we applied a multiple-trial version of the classic TAF experiment and evaluate two variables, reaction time (RT) and emotional intensity (EI).

METHODS

Ninety-three patients with OCD and 45 healthy controls (HCs) were recruited. The participants were asked to read the name of a close or neutral person embedded in different positive (PS) or negative (NS) TAF statements. During the experiments, RT and EI were gathered.

RESULTS

The OCD patients presented with longer RT and lower EI in the NS condition than HCs. In each group, the HCs showed a significant relationship between RT in the NS condition and TAFS scores, whereas the patients did not, although they had higher TAFS scores than the HCs. In contrast, the patients showed a trend toward a correlation between RT in the NS condition and guilt.

CONCLUSION

These findings may indicate our multiple-trial version of the classical TAF showed reliable results of the two new variables, especially RT, in the task and allow to newly identify paradoxical patterns in which the TAFS scores are high but actual performance is impaired, that is, the inefficient activation of TAF in OCD.

Anatomical distance affects functional connectivity at rest in medicine-free obsessive-compulsive disorder

BACKGROUND

Brain functional abnormalities at rest have been observed in obsessive-compulsive disorder (OCD). However, whether and how anatomical distance influences functional connectivity (FC) at rest is ambiguous in OCD.

METHODS

Using resting-state functional magnetic resonance imaging data, we calculated the FC of each voxel in the whole-brain and divided FC into short- and long-range FCs in 40 medicine-free patients with OCD and 40 healthy controls (HCs). A support vector machine (SVM) was used to determine whether the altered short- and long-range FCs could be utilized to distinguish OCD from HCs.

RESULTS

Patients had lower short-range positive FC (spFC) and long-range positive FC (lpFC) in the left precentral/postcentral gyrus (t = -5.57 and -5.43; P < 0.05, GRF corrected) and higher lpFC in the right thalamus/caudate, left thalamus, left inferior parietal lobule (IPL) and left cerebellum CrusI/VI (t = 4.59, 4.61, 4.41, and 5.93; P < 0.05, GRF corrected). Furthermore, lower spFC in the left precentral/postcentral gyrus might be used to distinguish OCD from HCs with an accuracy of 80.77%, a specificity of 81.58%, and a sensitivity of 80.00%.

CONCLUSION

These findings highlight that anatomical distance has an effect on the whole-brain FC patterns at rest in OCD. Meanwhile, lower spFC in the left precentral/postcentral gyrus might be applied in distinguishing OCD from HCs.

Genetic Risk for Smoking: Disentangling Interplay Between Genes and Socioeconomic Status

This study aims to disentangle the contribution of genetic liability, educational attainment (EA), and their overlap and interaction in lifetime smoking. We conducted genome-wide association studies (GWASs) in UK Biobank (N = 394,718) to (i) capture variants for lifetime smoking, (ii) variants for EA, and (iii) variants that contribute to lifetime smoking independently from EA ('smoking-without-EA'). Based on the GWASs, three polygenic scores (PGSs) were created for individuals from the Netherlands Twin Register (NTR, N = 17,805) and the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2, N = 3090). We tested gene-environment (G × E) interactions between each PGS, neighborhood socioeconomic status (SES) and EA on lifetime smoking. To assess if the PGS effects were specific to smoking or had broader implications, we repeated the analyses with measures of mental health. After subtracting EA effects from the smoking GWAS, the SNP-based heritability decreased from 9.2 to 7.2%. The genetic correlation between smoking and SES characteristics was reduced, whereas overlap with smoking traits was less affected by subtracting EA. The PGSs for smoking, EA, and smoking-without-EA all predicted smoking. For mental health, only the PGS for EA was a reliable predictor. There were suggestions for G × E for some relationships, but there were no clear patterns per PGS type. This study showed that the genetic architecture of smoking has an EA component in addition to other, possibly more direct components. PGSs based on EA and smoking-without-EA had distinct predictive profiles. This study shows how disentangling different models of genetic liability and interplay can contribute to our understanding of the etiology of smoking.

Altered Functional Connectivity Strength at Rest in Medication-Free Obsessive-Compulsive Disorder

Background

Previous studies explored the whole-brain functional connectome using the degree approach in patients with obsessive-compulsive disorder (OCD). However, whether the altered degree values can be used to discriminate OCD from healthy controls (HCs) remains unclear.

Methods

A total of 40 medication-free patients with OCD and 38 HCs underwent a resting-state functional magnetic resonance imaging (rs-fMRI) scan. Data were analyzed with the degree approach and a support vector machine (SVM) classifier.

Results

Patients with OCD showed increased degree values in the left thalamus and left cerebellum Crus I and decreased degree values in the left dorsolateral prefrontal cortex, right precuneus, and left postcentral gyrus. SVM classification analysis indicated that the increased degree value in the left thalamus is a marker of OCD, with an acceptable accuracy of 88.46%, sensitivity of 87.50%, and specificity of 89.47%.

Conclusion

Altered degree values within and outside the cortical-striatal-thalamic-cortical (CSTC) circuit may cocontribute to the pathophysiology of OCD. Increased degree values of the left thalamus can be used as a future marker for OCD understanding-classification.

Korean Version of the Thought-Action Fusion Scale: The Evidence for Its Psychometric Properties

OBJECTIVE

The Thought-Action Fusion Scale (TAFS) is a self-reported instrument used to measure a cognitive bias, namely, thoughtaction fusion (TAF), in which intrusive thoughts have moral and actual consequences. The aim of this study is to investigate the reliability and validity of the Korean version of the 19-item TAFS (K-TAFS) in Korean samples.

METHODS

In this study, 628 university students and 93 patients with obsessive-compulsive disorder (OCD) completed the K-TAFS and several other psychological scales. Descriptive analyses, correlations, group comparisons, and exploratory and confirmatory factor analyses were performed.

RESULTS

The results of the exploratory and confirmatory factor analyses indicated a two-factor structure with TAF-Morality and TAFLikelihood that best fits the data in the university sample. The reliability analyses showed that TAFS and its factors had excellent internal consistencies. Regarding the concurrent validity, positive correlations were observed between TAF-Likelihood and cognitive fusion, while the TAFS scores did not show any consistent correlations with other symptoms such as depression and anxiety. Compared to the university students, the OCD patients showed higher TAFS scores and their obsessive-compulsive symptoms were significantly associated with both TAF-Morality and TAF-Likelihood.

CONCLUSION

Overall, the findings of this study support the reliability and validity of the K-TAFS.